Mechanochemical Activation and Agglomeration of Tungsten and Its Mixtures with Copper and Nickel
ANDREY N. STRELETSKII1, VALERY K. PORTNOY2, ALEXANDER V. LEONOV2, ANNA B. BORUNOVA1, PAVEL F. PSHECHENKOV3, IL'YA O. LEYPUNSKY3, NADEZHDA G. BERIOZKINA3 and PAVEL P. BU
1N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences,
Ul. Kosygina 4, Moscow 117977 (Russia), E-mail: str@centere.chph.ras.ru
2M. V. Lomonosov State University, Vorobyevy gory, Moscow 117899 (Russia)
3Institute of Energetic Problems of Chemical Physics, Russian Academy of Sciences, Leninsky Pr., Moscow 117829 (Russia)
Pages: 187-196
Abstract
Defect formation and activation of agglomeration during mechano-chemical treatment of tungsten powder and its mixtures with copper and nickel are considered. Mechano-chemical activation in high-energy strain mills is accompanied by the decrease of coherent lengths (to 10 nm), accumulation of microdeformations (up to 0.2-0.3 %) and increase of tungsten lattice parameter, as well as by profound mixing of the components. Besides, the system gets contaminated with iron impurities. Chemical transformations during the annealing of samples with different doses of mechanical treatment are analyzed. The application of mechanochemical activation allowed us to obtain well agglomerated W/Ni/Cu alloys at annealing in the absence of hydrogen (density: up to 16 g/cm3; Wickers' hardness: up to 550 kg/mm2). Optimal dose of mechano-chemical activation is determined (10-115 kJ/g); optimal regime of powder pressing is revealed. The effect of iron impurities on the hardness of agglomerated tablets is investigated.
|
